Cleated chain wrench

Abstract

A chain wrench has a handle having a chain element pivoted to the handle by a pair of links to permit passage of the free end of the chain between the links, whereby the chain may be wrapped in full circumscribing relation to a workpiece. The handle has a camming surface and teeth elements positioned to confront the exposed surface of the chain when it is wrapped around the workpiece. The chain has a cleated surface on one side and has a smooth surface on the opposite side. In one mode of operation, the cleated surface confronts the workpiece to engage the same, whereby the cam surface causes the cleats to grip the workpiece and anchor the chain at that point when said handle is actuated to apply torque to the workpiece, the smooth surface permitting the chain to slide over said camming surface prior to applying torquing action upon said handle to afford snug engagement of the chain about substantially the entire circumference of the workpiece. In another mode of operation, the smooth surface of the chain confronts the workpiece and the cleated surface is exposed when it is wrapped around the workpiece. The teeth elements of the handle engage the cleated surface of the chain so that the cleats mesh with the teeth of the handle to tighten the chain around the workpiece when the handle is actuated to apply torque to the workpiece. The chain may be either a link-type chain having metallic links, or a strap of textile material which may be used when the workpiece has a high finish which may be easily damaged by either surface of the chain. Preferably, the wrench provides two chain elements which may be used interchangeably.

I claim: 
     
       1. A wrench comprising a handle having an enlongated grip portion and an enlarged head portion, spaced parallel link elements pivoted to said handle by a pivot pin passing through said enlarged head portion, a fastener at the remote end of said link elements disposed in spaced relation to said head portion, a chain element pivoted on said fastener between said links and having a free end portion adapted to pass between said links in the space between said fastener and said head portion, whereby the chain may extend from said remote fastener in full circumscribing relation to a workpiece and pass between said handle and said remote fastener, said chain comprising parallel pointed cleats extending transversely the full width of the chain on one surface thereof and a smooth back on the other surface thereof, a camming surface on said head portion remote from the pivot pin mounting said links and positioned to confront the exposed surface of the chain when it is wrapped around the workpiece in one direction with the cleats engaging the workpiece and said camming surface operable to bear against the smooth back of the chain in the portion of the chain circumscribing said workpiece to thereby securely anchor the chain against the workpiece, said camming surface being convex and of sufficient length to permit said camming surface to be the sole anchoring means for said wrench upon torque being applied to workpieces having differing diameters, said head portion including a plurality of teeth centered about the pivot pin for said link elements and projecting radially outward to confront the cleated surface of the chain when it is wrapped around the workpiece in the opposite direction with the smooth sides of the chain bearing against the workpiece, said teeth meshing with said cleats to securely tighten the chain around said workpiece upon application of torque by said handle, whereby said wrench is operable to engage the workpiece either with the pointed teeth of the cleated side or with the smooth surface of the smooth side. 
     
     
       2. A wrench according to claim 1 wherein said chain is a link-type chain comprising transverse rows of link plates having link pins connecting the link plates to each other in rows, said link plates of each row being interdigitated with respect to the link plates of an adjacent row, each of said link plates having a pair of teeth disposed on the same side of the plate and a rounded back portion on the opposite side of said plate forming the smooth back surface of the chain, the teeth of said interdigitated link plates being aligned transversely to form said pointed cleats across the full width of the chain, when the chain is wrapped around the workpiece in one direction, said camming surface operable to bear against the smooth side of the chain links, and when the chain is wrapped around the workpiece in the opposite direction, said teeth of the head portion meshing with the teeth of the interdigitated link plates. 
     
     
       3. A wrench according to claim 1 wherein said chain is woven textile flexible strap element having a smooth surface on one side and a layer of plastic material forming cleats on the other side, said cleats conforming to the teeth of said head portion. 
     
     
       4. A wrench according to claim 1 wherein said remote fastener is a releasable fastener operable to selectively fasten a chain element to said parallel link elements. 
     
     
       5. A wrench according to claim 1 wherein said convex camming surface has a uniform radius of curvature approximately one-fifth of the axial length of the handle gripping portion.